1. Technical Field
The present invention relates to a sliding device.
2. Background Art
Generally, a sliding device is installed between a stationary support and a movable body which slides with respect to the stationary support to enable a user to put an object into the movable body to store it or extract the object therefrom. The sliding device is configured so as to be slidable so that the movable body is easily extracted from or refracted into the stationary support. A drawer which can store objects therein and is a container with no lid is a representative example of such a movable body. Typically, drawers are connected to sliding devices fastened to stationary supports, such as furniture, refrigerators, ovens, casings of electronic products, etc.
As stated above, sliding devices are used in a variety of stationary supports. Such stationary supports can include all objects to which the sliding devices can be fastened. The movable bodies are objects which can be extracted from or retracted into the stationary supports. Such movable bodies can include all objects which can be connected to the sliding devices and slide with respect to the stationary supports.
In this specification, for the sake of explanation, such a movable body will be designated as a drawer, and such a stationary support will be designated as furniture.
Of course, it will be easily understood that the drawer implies all movable bodies, and the furniture implies all stationary supports.
Drawers are provided in various kinds of furniture so that the drawers are extracted from furniture to open and retracted thereinto to close. Drawers have no lid so that when they open, users can easily observe objects contained in the drawers and easily take them out of the drawers. When the drawers are closed, they are completely retracted into the furniture without a protruding portion. Thus, the appearance of the furniture can be maintained as superior or decorative. Therefore, the drawers are widely used in furniture, such as desks, wardrobes, dressing tables, stationery cases, etc., because of the facility of storage of objects or removing them.
As mentioned above, a drawer slides with respect to furniture when it is extracted from or retracted into the furniture. Typically, sliding devices are provided at both sides of the drawer so that the drawer can slide with respect to the furniture.
Sliding devices are classified into a double-folding type and a triple-folding type. A triple-folding type sliding device includes a stationary member which is fastened to furniture, an intermediate member, and a movable member which is fastened to a drawer. The first end of the intermediate member comes into rolling contact with the stationary member, and a second end thereof comes into rolling contact with the movable member. Thereby, the movable member is slidably connected to the stationary member. Rolling tracks are formed on the first and second ends of the intermediate member to bring the intermediate member into rolling contact with the stationary member and the movable member. In addition, rail tracks are formed in the stationary member and the movable member at positions corresponding to the rolling tracks. Balls are provided between the rolling tracks and the rail tracks. When a user pulls a drawer, the balls roll in the sliding device so that the drawer smoothly slides outward with respect to the furniture. Thus, the drawer can be easily extracted from the furniture. When the user pushes the drawer which has been extracted, the drawer smoothly slides inward with respect to the furniture due to the rolling motion of the balls, so that the drawer can be easily retracted into the furniture.
Meanwhile, force generated by the weight of the drawer and objects contained in the drawer is applied to the drawer which is extracted from or retracted into the furniture. The force is transmitted to the furniture via the sliding devices provided at both sides of the drawer. Therefore, the sliding device must have a structure that can resist such force.
FIG. 1 is a sectional view showing a conventional sliding device 10 disclosed in U.S. Pat. No. 6,132,020. As shown in FIG. 1, the conventional sliding device 10 includes a movable member 13, a stationary member 17 and an intermediate member 14 which is interposed between the movable member 13 and the stationary member 17.
In the conventional sliding device 10, the stationary member 17 is fastened to a sidewall panel 16 of a body of, for example, a desk, by an extension 12. The movable member 13 is fastened to the lower surface of a drawer panel 11. Three tracks are formed on each of both ends of the intermediate member 14.
Balls 15 are provided between the movable member 13 and the intermediate member 14 and between the intermediate member 14 and the stationary member 17. The balls 15 roll along the corresponding tracks so that the intermediate member 14 slides along the stationary member 17 and the movable member 13 slides along the intermediate member 14. Accordingly, the sliding device 10 is generally operated in a triple folding manner.
In this conventional sliding device 10 of U.S. Pat. No. 6,132,020, three rows of tracks are formed on the upper and lower sides in a shape in which they face each other to offer resistance to the force. The movable member 13 is open both on a side surface which is adjacent to the center of the drawer panel 11 and on the bottom thereof. The movable member 13 has tracks formed on an upper corner which is adjacent to the center of the drawer panel 11 and on upper and lower corners which are adjacent to the sidewall panel 16. The stationary member 17 is open both on a side surface which is adjacent to the center of the sidewall panel 16 and on the top thereof. The stationary member 17 has tracks formed on a lower corner which is adjacent to the sidewall panel 16 and on upper and lower corners which are adjacent to the center of the drawer panel 11. The intermediate member 14 has tracks at corresponding positions such that the tracks of the intermediate member 14 come into rolling contact with the balls which are in rolling contact with the tracks formed on the movable member 13 and the stationary member 17.
In the conventional sliding device 10, as shown in the sectional view of sliding device 10, the balls 15 which are located in the movable member 13 at the upper and lower positions adjacent to the sidewall panel 16 and the ball 15 which is located at the upper position adjacent to the center of the drawer panel 11 form an approximately triangular shape. These balls 15 along with the intermediate member 14 support the force generated by the weight of the drawer panel 11 and objects contained in the drawer. Furthermore, the balls 15 which are located in the stationary member 17 at the upper and lower positions adjacent to the center of the drawer panel 11 and the ball 15 which is located at the upper position adjacent to the sidewall panel 16 form an approximately triangular shape. These balls 15 along with the intermediate member 14 support the force. In other words, the corresponding balls 15 are located on the upper end of the intermediate member 14 into a triangular shape of which the vertex is oriented toward the sidewall panel 16. In addition, the corresponding balls 15 are located on the lower end of the intermediate member 14 at positions facing the balls 15 on the upper end thereof into a triangular shape of which the vertex is oriented toward the center of the drawer panel 11. As such, in the conventional sliding device 10, the balls 15 are disposed at both sides of the lower surface of the drawer panel 11 so that the balls face each other with respect to the vertical direction. Hence, the sliding device 10 can offer resistance to a force applied thereto downward.
However, the conventional sliding device is configured so that six rows of tracks on the upper and lower sides are formed, and the movable member, the stationary member and the intermediate member come into rolling contact with the balls to form the sliding structure. Thus, the structure of the six rows of tracks and the rolling structure of the balls in contact with the tracks make it difficult to reduce the volume of the sliding device.
Furthermore, because the conventional sliding device requires the forming of the six tracks on the intermediate member, the shape of the intermediate member is complicated, so that it must be manufactured by bending a plate several times into a complex shape. Manufacturing the intermediate member with the complex shape causes an increase in the production cost.
Moreover, when the drawer is extracted from the furniture, force generated by the weight of the drawer and the objects contained in the drawer is concentrated on a lower portion of the drawer in the direction in which the drawer is extracted. This force concentrated on the lower portion of the drawer acts as torsional force applied to the sliding devices which are fastened to both sides of the drawer. In other words, when the force is concentrated on the lower portion of the drawer in the extraction direction, torsional force is applied toward the center of the drawer to each of the sliding devices which are located at both sides of the drawer. However, in the conventional sliding device, because the six rows of tracks are formed facing each other in the movable member coupled to the drawer and the stationary member fastened to the sidewall panel of the desk so as to offer resistance to the force applied to the drawer panel in the vertical direction, resistance to torsional force applied to the sliding device toward the center of the drawer is markedly reduced. In detail, because the six rows of tracks and the balls seated into the tracks are configured so as to offer resistance to force applied to the drawer downward, they may be easily influenced by torsional force. As such, in the conventional sliding device, the six rows of tracks disposed at both sides of the drawer so as to resist force applied to the drawer downward in the vertical direction and the balls provided on the respective tracks cannot reliably resist the torsional force applied to the sliding device toward the center of the drawer.
When such torsional force is applied to the conventional sliding device for a long period of time, the movable member and the stationary member may be deformed, thus increasing the clearance of the drawer. As a result, the lifespan of the sliding device may be reduced.
Moreover, after the drawer has been extracted, downward force is applied to the outer end of the sliding device that is a leading end with respect to the extraction direction of the drawer, and upward force is applied to the inner end of the sliding device that is opposite to the leading end. The upward force and the downward force are uniformly dispersed when the number of tracks is two to the power of n, where n is an integer. In other words, in a sliding device, the number of tracks which are provided between the intermediate member and each of the movable and stationary members coming into rolling contact with the intermediate member must be the power of two, so as to uniformly disperse the upward force and the downward force. That is, in the case where the number of tracks is the power of two, one ball which comes into rolling contact with each track and another ball which corresponds to the ball are present in a pair so that the force applied to the sliding device can be uniformly dispersed. However, in the conventional sliding device, the three rows of tracks and the balls seated on the tracks are provided in each of the movable member and the stationary member. Thus, the upward force and the downward force are concentrated on a spot of the sliding device rather than being uniformly dispersed. Such concentration of force increases the clearance of the drawer with respect to a specific direction and causes torsion deformation of the drawer.
Therefore, a sliding device which can reliably support force applied to a drawer despite a minimized number of bearings is required.
In particular, development of a sliding device is required, which is configured so that when it is installed at each of both sides of a drawer and supports the weight of the drawer, resistance to torsional force applied thereto toward the center of the drawer is enhanced so that the lifespan thereof can be extended.